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F6 vs. M2. As the previous page's intro list showed, the very first Watt models F1 and F2 had subsequently enjoyed a J-fitted remake which traded the original Mosfets for power Jfets. The F3 and J2 always ran on those, the SITs on their own version. It takes zero feedback to suspect that Nelson has developed special affection for power Jfets which previously existed only in specs suitable for low-level circuits like preamps. The latest variants still don't make tons of power but have grown sufficiently hung for the kind of SET-ish amps FirstWatt specializes in for the non-tube listener. Seeing how in my estimation the most sophisticated sound of the lot is made by the SITs followed by the J2—I'd only heard the F1/F2 with Mosfets to qualify that statement—I entered this comparison feeling predisposed to preferring the F6 for its Jfet where the M2 drives the mossy sort. Of course if I did prefer the F6 I'd have no way of knowing whether the reason really was its type of transistors. That's where reviewers are pathetically incapable. We can describe sonic differences, we can guess at contributory factors but we can never with total conviction pronounce that X sounds better because.

That doesn't prevent writers from championing causes. If your favorite five speakers all use sealed bass loading, ribbon tweeters and 1st-order filters, you can be reasonably excused for believing that those particular facts cause your fancied sound. If this subsequently leads you to only review speakers of their kind, you should develop a growing body of proof which supports your cause like self-fulfilling prophecy. It also isolates you strategically from opportunities to encounter equivalent or better sound produced by very contradictory means. We all do this to various degrees. I believe it's this very tendency to bulk up assumptions (then becoming selective because of them plus wanting to be experts in something, perhaps even educate others) which creates the type of urban myths hifi is full of. One such myth is the badness of negative feedback. Nelson himself has presented convincing evidence for why. Yet the F6 brazenly embraces NFB. That's the difference between religious intolerance and true curiosity. It's what makes Nelson Pass a true master. He stays curious. He keeps tasting all manner of forbidden fruit. That's the road to progress and how one makes unexpected finds.

En pointe now. A reader with Avantgarde Acoustic hornspeakers had tried a SIT2, called it noisy and settled on the M2 as ideal instead. This choice I couldn't comprehend. My experience calls the M2 the 'noisiest' of all the very quiet FW amps. This juxtaposition confirmed it once again. My current conventional dynamic speakers really aren't sufficiently efficient to become noise-tracking blood hounds like 107dB horns. To me noisier means lower resolution and narrower dynamic range from higher system noise floor. This you don't hear per se—pause means your system makes no sound, period—but you hear it as diminished visibility of the micro stuff and how it flattens out some inflective ripples in instrumental or vocal deliveries. It's exactly what one notices with superior AC filtering/DC blocking like the Spanish Vibex powerline kit.

The M2 was my system prior to the Vibex DC blockers. It was softer, gentler, more shadowy. It created greater energetic distance without shifting the actual perspective on the soundstage. If we talk of our virtual performers as sculptures being freshly chiseled out in deep stone relief or softened by centuries of exposure to the elements, the F6 was fresh from the yard, the M2 smoothed over from years of weather beating. Its relief was shallower, its edges rounder. Its ability to render textural variety from fine degrees of transient spiciness—a soft bow whisk, a pert metal ping, a plectrum-picked string, a swirled brush, a spitty horn blow all have different attack sharpness—played with a narrower palette. On hyper-acute horn speakers with very steep rise times, the M2's minor vagueness could well be the perfect antidote to what hifi lingo calls etchiness. With my less aspirated transducers I instead needed/wanted more edge definition. Here the F6 had my vote. That greater 'edginess' needn't be nervous, restless, trying, annoying or any other flavor of objectionable is a special virtue of Nelson's favored power Jfets I think.
They're lit up in the sense of non-obscured but without the unnatural tinge of neon or fluorescent lighting. They're minorly sweet without the limpid effect of pure gold cables which bleed out music's inherent tension. They're sophisticated in their delivery but not coy about getting down into grittier uglier grooves. To wrap up the M2 visitation, my prior take on it is unchanged. With my speakers and current tastes it's my least favorite amp of this stable. It seems to make a few steps backwards from the ground the F5 had already covered. That's our signal to change horses. The F5 and F6 not only have the numerology thing going for tight sibling sport, they're close power rivals in their suitability for more conventional less specialized speakers. With the F5 discontinued now, the F6 pure DIY, either requires rolling your own.